In power systems using a configuration of parallel switched mode voltage regulators, the individual regulators share the same control voltage and will provide a substantially equal amount of current to the load. The parallel regulator configuration generally comprises one master or controlling regulator, the remaining regulators being designated slave or controlled regulators. Problems exist upon failure of the master and/or slave regulators, both in providing load current and identifying the specific failed regulator. This is particularly true in the failure of the master or control regulator which generates the error signal for controlling operation of the slave regulators in a parallel regulator configuration. The diagnostic system of the instant invention identifies the failed regulator rapidly and replaces the failed device with a redundant regulator in the system to eliminate down time for the associated power system.